Post Office Box-Plug Type (Constantan and Manganin Coil) Manufacturer,Supplier and Exporter in India
Product Code : ILS-PLE-10137
Indian Lab Suppliers supplies the Post Office Box-Plug Type (Constantan and Manganin Coil) (Product ID: 10137) as part of its physics lab equipment range. It is a plug-type Wheatstone bridge in a single box, used to measure unknown resistances.
Quick Answer
Two versions are made. The 3-ratio box has sixteen non-inductively wound coils of 1, 2, 2, 5, 10, 20, 20, 50, 100, 200, 200, 500, 1000, 2000, 2000 and 5000 Ω (11,110 Ω in all) and two ratio arms of 10, 100 and 1000 Ω each; with ratios up to 100:1 it measures from about 0.1 Ω to 1,111,000 Ω with a DC cell. The 4-ratio box has the same sixteen coils, ratio arms of 1, 10, 100 and 1000 Ω, and an infinity gap. Two spring keys for the battery and galvanometer circuits are built in. Manganin coils give ±0.05% accuracy and constantan coils ±0.1%.
Key Specifications
| Parameter | Detail |
|---|---|
| Versions | 3-ratio and 4-ratio |
| Coils | 16: 1, 2, 2, 5, 10, 20, 20, 50, 100, 200, 200, 500, 1000, 2000, 2000, 5000 Ω |
| Ratio arms | 3-ratio: 10, 100, 1000 Ω; 4-ratio: 1, 10, 100, 1000 Ω plus infinity gap |
| Coil wire and accuracy | Manganin ±0.05%; constantan ±0.1% |
| Keys | 2 spring keys (battery and galvanometer) |
| Construction | Rectangular brass blocks 12 mm or 14 mm thick, in a wooden box |
Where This Is Used
Used in college practicals on the Wheatstone bridge and the specific resistance of a wire. For supplying known resistances only, the Resistance Box (Product ID: 10133) is simpler. Browse the full Physics Lab Equipment range or related Electrical and Electronics products.
Frequently Asked Questions
What is the difference between the 3-ratio and 4-ratio boxes?
The 4-ratio box adds 1 Ω coils to each ratio arm and an infinity gap, giving a wider choice of ratios.
Manganin or constantan coils?
Manganin gives ±0.05% accuracy, constantan ±0.1%.
Are the keys included?
Yes, two spring keys for the battery and galvanometer are built in.
Related Categories
Physics Lab Equipment · Electrical and Electronics · Electricity and Magnetism
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